Power conversion systems and methods for controlling harmonic distortion

Abstract

Control systems, methods and power conversion systems are presented for controlling harmonic distortion, in which multi-sampling space vector modulation (SVM) is employed for controlling power converter switching devices, with a reference vector being sampled two or more times during each SVM period to update the SVM dwell times more than once during each SVM cycle.

Description

FIELD OF THE INVENTION[0001]The present disclosure relates generally to electrical power conversion and more particularly to controlling harmonic distortion in motor drives and other power converters.BACKGROUND OF THE INVENTION[0002]Power conversion systems convert electrical power from one form to another and may be employed in a variety of applications such as motor drives for powering an electric motor using power from an input source. Such power converters have been extensively employed in medium voltage motor drives and other applications in which electrical power needs to be converted from DC to AC or vice versa. Typically, the power converter is constructed using electrical switches actuated in a controlled fashion to selectively convert input power to output power of a desired form such as single or multi-phase AC of a controlled amplitude, frequency and phase to drive an AC motor according to a desired speed and / or torque profile, often in the presence of varying load condi...

AI Technical Summary

Problems solved by technology

However, the modulation index of SHE is usually fixed due to implementation difficulties, and thus the SHE modulation approach typically does not allow control flexibility.

Conventional SVM and TPWM modulation techniques allow modulation index adjustment, but generally suffer from high levels of low order harmonic distortion, particularly the 5th and 7th harmonics that are often close to the resonance frequency of motor drive AC filters.

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